We needed a server solution for both files and applications
Not specifically familiar.
I was looking into it myself. Though I am not sure what you mean by "for ... applications". A NAS is an excellent idea for file storage (especially if you have some form of RAID that might keep your data more reliably available).
A full blown server might do a lot more than just a NAS, such as run a database (which requires actual processing power, not only storage), and various daemons and/or server applications.
